AQTEBLOG (The AQTESOLV Blog)

Fort Collins 2011

2011-10-11T08:39:00.000-05:00

I'm back from another well-attended aquifer testing short course held at the headquarters of In-Situ, Inc.on October 5 and 6, 2011 and the sixth consecutive year that we've traveled to Ft. Collins, CO to present Aquifer Testing for Improved Hydrogeologic Site Characterization Featuring AQTESOLV and the In-Situ LevelTROLL.

Analysis of recovery data combining Agarwal method and derivative analysis.

The course covered topics relating to designing, performing and analyzing both slug tests and pumping tests and included hands-on use of AQTESOLV as a teaching tool. As part of my lectures, I spent a good deal of time going over the finer points of diagnostic methods for pumping tests including derivative analysis, a technique widely practiced in the petroleum industry for well test analysis. I further introduced the class to the Agarwal method for analyzing recovery tests which also drew a lot of attention.

Thanks to all who attended the course and to In-Situ for hosting us! I look forward to doing it again next year.

Enhancing Reliability of Slug Test Data Analysis

2011-08-30T17:49:00.000-05:00

Data from an overdamped slug test in a well with a fully submerged screen (screen below water table) may exhibit a concave upward appearance on a plot of log normalized head vs. time. The curvature can make analysis by straight-line methods such as Bouwer and Rice (1976) somewhat ambiguous.

Analysis of slug test data using recommended normalized head range.

Butler (1998) suggests matching straight-line slug test solutions to data within recommended normalized head ranges to overcome ambiguity associated with slug test data curvature and thereby enhance the reliability of data analysis. AQTESOLV includes the recommended normalized head ranges to assist you with visual curve matching.

Learn more about recommended normalized head ranges in Aquifer Testing 101 at the AQTESOLV web site.

Summit in Lawrence, Kansas

2011-07-20T10:53:00.022-05:00

On today's date in 1969, Neil Armstrong made history by becoming the first man to walk on the moon. Forty-two years later, July 20th marks another red-letter day with the conclusion of the 1^st Lawrence Summit hosted by Jim Butler and attended by Dan Kelleher and myself. The summit met its primary goal of laying the groundwork for future aquifer testing short courses around the world.

GEMS Research Site (Butler et al. 2000)

Unforgettable moments during the visit included a tour of the venerable Kansas Geological Survey and its GEMS research site, a view of the Allen Field House from Jim's bleacher seats ("Rock, Chalk, Jayhawk!") and a reverential pilgrimage to the James Naismith ("Inventor of Basketball") Memorial. Without question, though, the unsurpassed highlight of the summit was the delightful sushi dinner served to perfection by Jim's daughter, Mai. Many thanks to Jim and wife Yun for their warm hospitality throughout the Lawrence Summit!

Agarwal Recovery Method

2011-07-14T21:26:00.001-05:00

In yesterday's post, I presented three different methods for analyzing recovery tests. Today, I will focus on the Agarwal recovery method which has been used by petroleum engineers for over 30 years. Agarwal (1980) devised a simple yet powerful data transformation for the interpretation of recovery tests. The transformation, known as Agarwal equivalent time, allows one to analyze recovery data with standard type curves developed for drawdown data.

The following figure illustrates the simplicity of the Agarwal method in the analysis of a recovery test. In this example, I matched the familiar Theis type curve, normally applied to drawdown data, to estimate aquifer properties from recovery test data (USBR 1995).

Agarwal recovery analysis using Theis (1935) solution.

Many different pumping test solutions may be used in conjunction with the Agarwal technique as well as diagnostic methods such as derivative analysis. The figure below shows recovery and derivative data matched together with the Cooper-Jacob straight-line solution.

Agarwal recovery analysis using Cooper-Jacob (1946) solution with derivative.

Recovery test analysis with the Agarwal equivalent-time method is available in AQTESOLV v4.x. The software allows you to estimate aquifer properties by matching both recovery and derivative data together.

Learn more about the Agarwal method in Aquifer Testing 101 at the AQTESOLV web site.

Analyzing Recovery Tests

2011-07-13T17:31:00.011-05:00

Did you know that AQTESOLV v4.x provides three different methods for the analysis of recovery tests?

Method 1: Combined analysis of drawdown and recovery data.

Method 2: Analysis of residual drawdown data.

Method 3: Analysis using Agarwal (1980) method.

The foregoing figures illustrate the use of the three recovery test methods in the analysis of a field example reported in the Ground Water Manual (USBR 1995). The results show that one may obtain consistent aquifer property estimates with all three techniques.

Learn more about the three methods of recovery analysis in Aquifer Testing 101 at the AQTESOLV web site.

Groundwater Mounding

2009-11-01T12:28:00.038-05:00

Upon its release in 2006, AQTESOLV/Pro v4.0 became the first aquifer testing software to feature groundwater mounding calculators that predict the transient rise and decay of the water table beneath rectangular and circular recharge areas (Hantush 1967). Using AQTESOLV, you may compute the maximum rise of the water table and generate contours of a groundwater mound with ease.

The example plot (above) shows a 3-D contour plot of a groundwater mound developed around a hypothetical rectangular recharge area. Applications for the groundwater mounding calculators in AQTESOLV include infiltration from septic systems and recharge from stormwater impoundments.

Visit the AQTESOLV web site for more information on the Hantush (1967) solutions for groundwater mounding prediction.

ASTM "Standards"

2009-06-20T16:24:00.024-05:00

ASTM publishes "standards" on many subjects including aquifer test analysis. ASTM D5912-96 (2004) entitled Standard Test Method for (Analytical Procedure) Determining Hydraulic Conductivity of an Unconfined Aquifer by Overdamped Well Response to Instantaneous Change in Head (Slug) is one such ASTM standard. You'll spend $32 to obtain a copy of this four-page standard from ASTM, but don't expect to get completely accurate information for your investment.

ASTM D5912-96 (2004) describes a widely used method of slug test analysis devised by Bouwer and Rice (1976). The standard contains an equation (ASTM D5912-96 (2004), p. 2, Equation [2]) used in the Bouwer and Rice method to calculate the parameter ln(R_e/r_w) when D (the aquifer thickness) is greater than H (the penetration of the well) as follows:

The ln(R_e/r_w) parameter is used in the Bouwer and Rice method to calculate the hydraulic conductivity K from a slug test.

Unfortunately, the above equation from ASTM D5912-96 (2004) is incorrect. The correct form of this equation (Bouwer and Rice 1976, p. 425, Equation [8]) is written as follows:

As one can see from a comparison the two foregoing equations, the ASTM version misplaces the term L/r_w and leads to a completely erroneous estimate of ln(R_e/r_w).

Am I just nitpicking here? I don't think so. It's hardly unreasonable to expect thorough attention to detail from a publication put forth as a "standard" such as ASTM D5912-96 (2004). Certainly, the basic equations that are central to such a standard should be checked carefully and published without error. ASTM standards purportedly go through a rigorous review process. Yet ASTM D5912-96 (2004), adopted in 1996 and subsequently reapproved in 2004, still contains the flawed equation. One is left to wonder how many other "standards" relied upon for aquifer testing contain similar fundamental errors.

AQTESOLV in Boston

2009-04-28T09:23:00.012-05:00

Today marks the beginning of our three-day Advanced Aquifer Testing Techniques Featuring AQTESOLV: New Concepts, Field Methods and Data Analysis Procedures short course at the Waltham Wood Conference Center outside of Boston, MA. Presented in cooperation with the Midwest Geosciences Group, we have been offering this course every year since 2006. The course covers aquifer testing topics pertaining to slug tests and pumping tests. As part of each day's activities, course participants gain hands-on experience with the AQTESOLV software using data from real-life field investigations conducted in a variety of hydrogeologic settings.

Last year (2008) seemed to come and go very quickly owing to an extremely busy schedule! We presented our three-day aquifer testing course featuring AQTESOLV in San Antonio, TX to a large audience and also taught well-attended two-day seminars in Waterloo, ON, Canada as well as Ft. Collins, CO. A wonderfully exciting time for me was a three-week period in November and December 2008 when I traveled to Australia to participate in the instruction of short courses on fractured bedrock in Melbourne and Sydney.

Wellfield Simulations

2007-12-31T06:55:00.008-05:00

This will be my last post for 2007, so let me begin by expressing my sincere appreciation and gratitude to all of you who have either become new AQTESOLV customers or continued to support the software by upgrading in the past year. As always I'm working hard to add new features that will maintain AQTESOLV's status as the leading software for aquifer test analysis.

As many of you already know, AQTESOLV includes the capability to model more than one pumping well in either pumping test analyses or predictive simulations. You may enter a variable pumping rate schedule for each well. For example, you can use the multiple pumping well feature to predict total drawdown in a wellfield as shown in the contour plot.

Another use of this multi-well feature would be to include the effect of more than one pumping well in the analysis of a pumping test (e.g., a domestic well that turns on and off during your test). Image wells can be simulated in the same way.

Best wishes for a happy and healthy New Year!

NGWA Expo in Orlando

2007-12-09T10:29:00.004-05:00

On Thursday, December 6, I swooped into Orlando, FL for a brief visit to the 2007 NGWA Ground Water Expo held at the Orlando County Convention Center. In the afternoon, I gave an invited oral presentation entitled Aquifer Test Analysis: A Modern Approach as part of a special technical session on "Advances in the Water Well Industry Over the Past 20 Years" moderated by Bob Sterrett and John Jansen.

In my talk, I emphasized the important role of specialized computer software such as AQTESOLV in the analysis of aquifer test data. Particular advantages of computer-assisted analysis over traditional methods of interpretation include diagnostic tools (diagnostic flow plots and derivative analysis); choice of curve matching method (visual and automatic); and statistical methods for interpreting results. In addition, the most recently published mathematical solutions are simply not well suited to graphical analysis using type curve techniques due to the large number of type curves required for their application. Consequently, a modern approach to aquifer test analysis takes advantage of the power afforded by today’s specialized software.

From Ft. Collins to Ottawa

2007-10-26T18:23:00.003-05:00

We had another successful aquifer testing course featuring AQTESOLV at the headquarters of In-Situ, Inc. this year. The sold-out course was attended by a lively group of professionals who came to learn more about conducting and analyzing slug tests and pumping tests. Many thanks to In-Situ for hosting us at their facility in Ft. Collins, Colorado!

Right after the course in Ft. Collins, I traveled to Ottawa, Ontario, Canada to participate in a seminar taught by Christopher Neville (pictured at right with Jeff Simpson) at the 60th Canadian Geotechnical Conference/8th Joint CGS/IAH-CNC Groundwater Specialty Conference entitled Critical Thinking in Pumping Test Interpretation. I contributed a module on diagnostic methods applied to the analysis of pumping tests which covered the use of diagnostic flow plots and derivative analysis in the identification of different flow regimes that emerge in the course of pumping tests. Thanks to Chris for inviting me to participate in his great course!

On my second day in Ottawa, I joined Jeff Simpson from Aquatic Life, Ltd. in the exhibitors' area of the conference. Aquatic Life rents and sells environmental monitoring equipment including In-Situ sensors for pressure and water-quality parameters. In an earlier post, I wrote about our collaboration with Aquatic Life in presenting an aquifer testing course in Calgary, Alberta. It was great to work with Jeff again!

Full House in Ft. Collins!

2007-10-03T20:30:00.002-05:00

I'm pleased to report that we've once again filled our short course in Ft. Collins, CO to maximum capacity before the early registration deadline. Last year was our first time in Ft. Collins so we're now 2-for-2!

We're holding the two-day short course entitled Aquifer Testing for Improved Hydrogeologic Site Characterization Featuring AQTESOLV and the In-Situ Level TROLL at the headquarters of In-Situ, Inc. on October 16 and 17, 2007. The course will include presentations by Jim Butler and myself on topics relating to slug tests and pumping tests and also will give everyone the opportunity to use AQTESOLV in the hands-on analysis of real-world test data.

Thanks to everyone who registered for the course. I look forward to meeting all of you!

Day 2 in Calgary....

2007-08-17T08:42:00.003-05:00

Yesterday evening, Jeff Simpson (right) of Aquatic Life generously invited everyone attending the short course in Calgary to a local pub for refreshment and dinner. We had a great time getting to know people, learning about their work and discussing a wide range of topics. Many thanks to Aquatic Life!

Today we are covering pumping tests in the course. After an introduction to the design and performance of pumping tests by Jim Butler, Chris Neville and I will present some of the finer details of pumping test analysis such as diagnostics methods, single-well tests, step-drawdown tests and recovery tests, analysis of tests in buried channel (strip) aquifers, and new methods for analyzing pumping tests in unconfined aquifers.

In the afternoon, the class will perform computer exercises with AQTESOLV demonstrating the analysis of pumping tests in confined, leaky confined, unconfined and fractured aquifers. This year's course features a new exercise for a pumping test conducted in a buried channel aquifer in Saskatchewan, Canada.

To all of you who joined us in Calgary for this course, we thank you for coming! It's been a pleasure interacting with you over the last two days.

Stampeding into Calgary!

2007-08-16T09:13:00.003-05:00

Today marks the beginning of our two-day short course entitled Aquifer Testing for Improved Hydrogeologic Site Characterization Featuring AQTESOLV and the In-Situ Level TROLL at the University of Calgary in Canada. I'm extremely pleased to report that we reached maximum capacity in our first-ever attempt to conduct this course outside the US. Kudos to Aquatic Life and the Midwest Geosciences Group making this groundbreaking course a great success!

I'm joined in this course by two distinguished colleagues, Jim Butler (Kansas Geological Survey) and Chris Neville (S.S. Papadopulos & Associates). Today, we're covering slug tests through a combination of lectures and computer exercises involving AQTESOLV. As I compose this blog entry, Jim is describing the application and advantages of the pneumatic method of initiating slug tests which is still a new technique for many practicing hydrogeologists. In his lectures today, Jim will present many new tidbits of practical advice from his ongoing research that are not included in his book The Design, Performance, and Analysis of Slug Tests (Butler 1998).

In the afternoon, Jeff Simpson from Aquatic Life will demonstrate the application of pressure transducer equipment in the performance of slug tests and stress pitfalls to avoid when conducting these tests. Following Jeff's presentation, I'll lead the class through the hands-on computer analysis of slug tests using AQTESOLV.

It's a great day and great venue here at the University of Calgary. Many thanks to all those who came to attend the course!

AQTESOLV Version 4.5 is Here!

2007-08-12T05:29:00.003-05:00

I'm pleased to announce the release of AQTESOLV v4.5, the world's leading software for the analysis of pumping tests, slug tests and constant-head tests since 1989.

AQTESOLV/Pro v4.5 is the first commercially available software for aquifer test analysis to feature a new analytical solution by Tartakovsky and Neuman (2007). Unlike the familiar method by Neuman (1974) for pumping tests in unconfined aquifers, the Tartakovsky-Neuman solution incorporates effects of 3-D saturated/unsaturated flow to account for noninstantaneous drainage at the water table. I've optimized the numerical computations in AQTESOLV to maximize the speed and accuracy of this complicated solution.

Shown at right is a match of drawdown and derivative curves that I obtained with AQTESOLV's implementation of the Tartakovsky and Neuman solution for an observation well monitored during a pumping test on Cape Cod by the USGS (Moench et al. 2001). Note the response at intermediate time which shows gradual rather instantaneous drainage of water.

Also featured in AQTESOLV/Pro v4.5 is a version of the Dougherty and Babu (1984) finite-diameter well solution adapted for the analysis of step-drawdown tests. Unlike traditional methods for analyzing step tests, the Dougherty-Babu step-test solution considers the effect of wellbore storage on early-time drawdown data measured in the pumped well. It also accounts for partial penetration, wellbore skin and turbulent well loss. One of my customers has already applied this solution with excellent results!

AQTESOLV v4.5 comes with interface enhancements and a revised Help system to increase productivity. For more information or to order the software, please visit the AQTESOLV web site or contact me directly!

In-House Training at AESI

2007-05-21T06:45:00.002-05:00

I had the privilege last week to visit the offices of Associated Earth Sciences, Inc. (AESI) in Kirkland, WA to present an in-house training course featuring AQTESOLV. In the two days of the course, I presented lectures on the finer points of diagnostic methods for pumping test analysis (radial flow, linear flow and derivative plots) as well as techniques for getting the most from single-well pumping tests. Most of the course, however, was devoted to using AQTESOLV for the analysis of real-world problems from AESI's project files.

The project data covered a wide range of topics including single- and multi-well pumping tests; evaluation of wellbore skin factors; partial penetration effects; confined, leaky and unconfined conditions; flow to a well in a buried valley (strip) aquifer; and the application of straight-line and type-curve methods for the analysis of slug tests. Course participants gained direct experience with AQTESOLV in the analysis of these data.

It was a pleasure to work with the knowledgeable group of hydrogeologists from AESI who attended the course and I thank them for the hospitality extended to me during my stay in Kirkland.

Two-Day Short Course in Calgary!

2007-04-28T17:07:00.003-05:00

I'm very pleased to announce a two-day short course entitled Aquifer Testing for Improved Hydrogeologic Site Characterization Featuring AQTESOLV and the In-Situ LevelTROLL that will be held on August 16 and 17, 2007 in Calgary, Alberta, Canada.

This offering will reprise the very well-received course that we presented in Ft. Collins last year. The workshop covers both pumping tests and slug tests and combines lectures on state-of-the-art aquifer testing methods with hands-on use of AQTESOLV in the analysis of test data.

In addition to myself (Glenn Duffield, president of HydroSOLVE, Inc. and author of AQTESOLV), instructors for the course will include Jim Butler (2007 NGWA Darcy Lecturer and author of The Design, Performance, and Analysis of Slug Tests) and Chris Neville (Vice President and Senior Hydrogeologist with S.S. Papadopulos & Associates).

For more information, please visit the Midwest Geosciences Group web site. This course is offered in collaboration with Aquatic Life Ltd.

Horizontal Wells in AQTESOLV

2007-04-21T17:32:00.005-05:00

One of the new features introduced in AQTESOLV/Pro v4.0 is a solution for a pumping test conducted in an anisotropic confined aquifer with a horizontal well (Daviau et al. 1985). With this solution, you may analyze drawdown data from fully or partially penetrating observation wells to determine the following aquifer properties: T (transmissivity), S (storativity) and Kz/Kr (hydraulic conductivity anisotropy ratio).

The horizontal well solution in AQTESOLV has been benchmarked against published well function values (Clonts and Ramey 1986) as shown in the accompanying figure.

AQTESOLV provides options for uniform-flux and infinite-conductivity conditions at the horizontal well as well as variable rates, recovery, multiple horizontal wells and multiple observation wells.

Winding It Down in Vegas....

2007-03-22T16:12:00.002-05:00

Yesterday we spent a full day visiting and learning about the proposed Yucca Mountain Repository near Las Vegas, Nevada. Dave Buesch from the USGS led an in-depth facility tour and crammed it with fascinating facts and details about the site's history, hydrogeologic investigations and modeling studies. In addition to inspecting exposures on and around the facility, we had the unique opportunity to enter the proposed tunnel and see it up-close and personal. Everyone came away feeling well informed!

Today (Thursday) marks our second and final day of lectures covering such diverse topics as solute transport, isotope applications, analysis of single-well tests, remediation techniques and demonstration of computer applications for fractured media.

The course concluded with a popular section which invites course participants to discuss their own problems in fractured rock hydrology. Instructors and course attendees shared their views and experiences to the benefit of all.

Viva Las Vegas!

2007-03-19T20:47:00.002-05:00

This entry comes to you from sunny Las Vegas where for the next three days I'll be participating in a short course entitled "Improving Hydrogeologic Analysis of Fractured Bedrock Systems" being held at the University of Nevada Las Vegas.

The course, organized by the Midwest Geosciences Group, is a series of lectures and workshops intended to improve hydrogeologic analysis, enhance field observations and reduce uncertainty in projects involving fractured bedrock systems.

My contribution to the course includes presentations on the physics of fluid flow in fractured media, methods for analyzing aquifer tests in fractured rock and analysis of single-well tests as applied to fractured media.

In addition to myself, instructors for the course are Ken Bradbury (above), Maureen Muldoon, Chris Mulry, Dan Kelleher and Paul Kesich.

A highlight of the course is a trip inside the proposed Yucca Mountain repository on Wednesday. It promises to be an exciting three days!

All Good Things Must Come to an End...

2007-03-02T17:08:00.002-05:00

Our three-day aquifer-testing workshop in San Diego, CA concluded on Thursday afternoon. A quick review of the course feedback forms showed that all who attended were very pleased with the course and the instructors: Jim Butler, Glenn Duffield and Shlomo Neuman (right).

Here's what some of the participants had to say about what portion of the course was most valuable to them:

"Dr. Neuman's new solution [for pumping tests in unconfined aquifers]"
"Jim Butler's presentation on slug testing was excellent"
"Glenn Duffield's discussion concerning pump tests"
"The exercises were most valuable"
"Ability to bring my own data set for analysis"
"Diagnostic approach to pump test interpretation especially derivative use (and limitations)"
"Pretty much all of it"

On behalf of the other course leaders, I would like to say how much of a pleasure it was to meet and interact with all of you who came to the University of San Diego to attend our course. Like previous courses, the lectures often stimulated some very lively discussions between the presenters and the audience. We also had an opportunity to sit down and work with some of you on your current projects. We hope that you enjoyed these experiences as much as we did. Let me conclude by thanking each and every one of you for contributing to the success of the course.

From Slug Tests to Pumping Tests

2007-03-01T07:41:00.002-05:00

For the past two days, scientists and engineers attending our course "Advanced Aquifer Testing Analysis Featuring AQTESOLV" in San Diego, CA, have been gaining state-of-the-art and practical knowledge that they can apply in the design, performance and analysis of pumping tests and slug tests. Each day has started with lectures by Jim Butler and Glenn Duffield that introduce important new concepts and principles useful to the practicing groundwater professional who is responsible for conducting aquifer tests. By the end of each day, course attendees have reinforced what they've learned by analyzing real-world test data with the AQTESOLV software.

Most of this year's course contingent come from cities across the US, but we are also pleased to have with us participants from Canada, Sweden and even Australia!

As always, Midwest Geosciences Group has done a marvelous job of organizing and facilitating the course. It has also been a pleasure to work with the University of San Diego who has provided us with an excellent facility.

Today will mark the final day of the course. We're looking forward to talks in the morning by Dr. Shlomo P. Neuman of the University of Arizona on the analysis of pumping tests in unconfined aquifers and also multiaquifer systems. It promises to another exciting day!

Hello from Sunny San Diego!

2007-02-26T20:02:00.002-05:00

Tomorrow starts our three-day short course entitled "Advanced Aquifer Testing Analysis Featuring AQTESOLV: New Concepts, Field Methods and Data Analysis Procedures" at the University of San Diego, CA.

This is our second offering of this popular course which uses AQTESOLV as a teaching tool to illustrate important concepts and principles discussed in lecture presentations. Last year, we held the workshop at the University of Miami in Miami, FL. The course covers topics relating to slug tests and pumping tests.

This year, we're pleased and privileged to have two outstanding lecturers contributing to the course: Jim Butler, the 2007 NGWA Darcy Lecturer and author of "The Design, Performance and Analysis of Slug Tests," and Shlomo Neuman, Regents' Professor of Hydrology and Water Resources at the University of Arizona. Both Butler and Neuman have made significant contributions to the well hydraulics literature. I will also present lectures and lead hands-on use of the AQTESOLV software in solving applied aquifer testing problems.

The warm and sunny weather predicted for San Diego this week is quite a contrast to the conditions I left behind yesterday in northern VA (a so-called "wintery mix" consisting of snow, sleet, freezing rain and rain). With some luck, I'll bring back some of San Diego's weather with me to VA!

Welcome!

2007-02-24T16:19:00.003-05:00

Welcome to my blog for AQTESOLV, the world's leading software for the analysis of aquifer tests since 1989!

From time to time, I'll be posting news, views, tips and short course announcements pertaining to AQTESOLV. With the addition of this blog to our other online resources (web site, knowledge base, users' group and comparison guide), I hope that you'll be able to find all the information you need regarding AQTESOLV.

In my first post to this blog, I'd like to take a moment to express my heartfelt appreciation to all of you who have supported AQTESOLV through the years. It's been a pleasure to work with you and I look forward to many more years of our continued partnership.

Many thanks,
Glenn M. Duffield
president of HydroSOLVE, Inc. and developer of AQTESOLV